Find the curved surface area of the frustrum in the figure.

Assessment: JAMB UTME - Mathematics - 1990 Subject: General Mathematics

Question 1 Report

16

π \sqrt{10}

cm2

20

π \sqrt{10}

cm2

24

π \sqrt{10}

cm2

36

π \sqrt{10}

cm2

Answer Details

\frac{x}{4} = \frac{6 + x}{6}

6x = 4(6 + x) = 24 + 4x

x = 12 = c = $π R L - π L$

= $π (6) \sqrt{18^{2}} + 6^{2} - π \times 4 \times \sqrt{12^{2}} + 4^{2}$

= 6 $π \sqrt{360} - 4 π \sqrt{160}$

= 36 $π \sqrt{10} - 16 π \sqrt{10}$

= 20 $π \sqrt{10}$ cm2

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